1. Field of the Invention
The field of the invention is data processing, or, more specifically, methods, apparatus, and products for managing a solid state drive (‘SSD’) in a Redundant Array of Inexpensive Drives (‘RAID’).
2. Description of Related Art
Solid state memory devices, such as solid state drives (‘SSDs’) are typically configured with a predefined amount of memory space, referred to as the ‘over provisioned’ area, that is reserved and not accessible by a user. The over provisioned area includes spare memory cells that may be used for failover, when other memory cells outside of the over provisioned area fail. A cell may ‘fail’ in various ways including, for example, by being written to a predefined number of times.
A typical over provisioned area of an SSD may be configured at 28% of the total storage space for the drive. So, for example, a 256 Gigabyte (GB) SSD may include 200 GB of capacity available for access by a user with 56 GB reserved for the over provisioned area. Thus, the cells in the over provisioned area of an SSD may be used for failover of cells in the user accessible memory space up to the size of the over provisioned area. Once the capacity of failed cells in the user accessible memory space of the SSD equals the capacity of over provisioned area, any future failures of cells in the user accessible memory space reduces the available user capacity. As such, SSDs are typically configured to a read-only mode when the capacity of failed cells in the user accessible memory space is equal to the capacity of the over provisioned area. In the read-only mode, the SSD restricts all writes and allows only reads of data stored on the SSD.
Present RAID controllers, however, are not configured to address SSDs operating in read-only mode in a RAID.